INTRODUCTION TO COAL MINING WEIR INTERNATIONAL, INC. HISTORY OF COAL IN THE UNITED STATES . Coal was one of man’s earliest sources of heat and light . Coal was first discovered in the United States along the Illinois River in the 1670s . First commercial mining occurred near Richmond, Virginia in 1750 . Between 1850 to 1950, coal was the most important energy fuel in the country . Today, coal accounts for more than half of the electric power generation . Coal is also critical for supplying coke for the nation’s steel industry ORIGIN OF COAL . Most of the coal was formed about 300 million years ago . Remains of vegetation sank to the bottom of swamps, forming a soggy, dense material called peat . Deposits of sand, clay and other mineral matter buried the peat . Increasing pressure from deeper burial and heat gradually transformed the peat into coal . The formation of one foot of coal requires an estimated three to seven feet of compacted plant matter TYPES OF COAL . Coal is classified in four general categories or “ranks”: Anthracite Increasing rank Bituminous Increasing carbon content Sub-bituminous Lignite Increasing heating value . The ranking of coal is based primarily on its carbon content and calorific value . The amount of energy in coal is measured in British Thermal Unit (Btu) per pound . Approximately 90% of the coal in the US is in the bituminous or sub-bituminous category MINING METHODS Surface Mining Underground Mining . Surface mining is: . Underground mining is typically employed where surface mining is not economical Generally the least expensive and most productive mining method to extract coal . Major underground coal mining methods include: Typically used when the coal seam is relatively close to the Room-and-Pillar surface Longwall . Surface mining can recover nearly 90% of the coal from a reserve deposit . Depending on the mining method, underground mining recovers 45 - 60% of a reserve deposit by continuous miner methods and . Total annual US production from surface mining is 60% approximately 70% by longwall mining methods . Total annual US production from underground mining is 40% TYPES OF UNDERGROUND MINE ACCESS . The decision on type of access depends upon the coal seam’s location relative to the surface . Access to underground coal seams: Shaft Mine Slope Mine Drift Mine SHAFT MINE . Frequent choice for deep deposits . Vertical access openings are developed from the surface to the coal . The shaft provides access for personnel, coal removal and ventilation SHAFT MINE SLOPE MINE . Frequent choice for deep deposits . Frequent choice for shallow deposits . Access by driving an incline opening from the surface . The slope provides access for personnel, coal removal and ventilation . Conveyor belts are used to transfer coal from underground to the surface . Slope mines still require shaft openings for ventilation and at times personnel access Preparation Plant Surface Slope Conveyor Belt Coal Seam SLOPE MINE DRIFT MINE . Frequent choice for deep deposits . Frequent choice when the coal seam outcrops on the slope of a hill side . Entrance or entrances can be developed horizontally to access the coal seam . Provides least expensive access to the coal seam Surface Transfer House Preparation Coal Seam Plant Main Conveyor Belt DRIFT MINE ROOM-AND-PILLAR MINING . Most underground mines in the US use room-and-pillar mining methods . This method of mining is as follows: Excavate a series of tunnels or “rooms” in the coal seam using continuous miners, along with shuttle car/ram car haulage Leave columns or “pillars” of coal to help support the mine roof Install roof bolts using a roof bolting machine to provide additional support and protection for underground personnel ROOM-AND-PILLAR MINING EQUIPMENT . Major types of mining equipment in room-and-pillar mining include: Continuous Miner Shuttle Car/Ram Car/Continuous Haulage Scoop Roof Bolter Feeder Breaker RoofRoof Bolterbolter CoalCoal pillar Pillar ContinuousContinuous miner Miner FeederFeeder-breaker Breaker EntryEntry No.No. 5 5 EntryEntry No.No. 4 4 EntryEntry No. No. 3 3 ShuttleShuttle cars Cars PanelPanel Conveyor conveyor EntryEntry No. No. 2 2 EntryEntry No. No. 1 1 Cross-cuts Cross-Cuts ROOM-AND-PILLAR MINING Limestone/Sandstone Shale Sandy Shale Shale ROOF BOLTING IN UNDERGROUND MINES Legend: CM = Continuous Miner RB = Roof Bolter SC = Shuttle Car F = Feeder Breaker B = Belt Conveyor ---- = Haulage Routes ROOM-AND-PILLAR MINING SEQUENCE Legend: CM = Continuous Miner RB = Roof Bolter SC = Shuttle Car F = Feeder Breaker B = Belt Conveyor ---- = Haulage Routes ROOM-AND-PILLAR MINING SEQUENCE Legend: CM = Continuous Miner RB = Roof Bolter SC = Shuttle Car F = Feeder Breaker B = Belt Conveyor ---- = Haulage Routes ROOM-AND-PILLAR MINING SEQUENCE Legend: CM = Continuous Miner RB = Roof Bolter SC = Shuttle Car F = Feeder Breaker B = Belt Conveyor ---- = Haulage Routes ROOM-AND-PILLAR MINING SEQUENCE CONTINUOUS MINER JOY 12CM12 SHUTTLE CAR JOY 10SC32 SCOOP COAL HAULER RAM CAR ROOF BOLTER FEEDER BREAKER LONGWALL MINING . Two parallel sets of entries are excavated in the coal seam . These entries are connected at their far ends by another set of entries to form a block of coal, referred to as the “longwall” . Typically, the block of coal is 1,000 feet wide and over one mile long . A rotating shearer or plow traverses across the block cutting the coal . Hydraulic roof supports advance with the shearer or plow while the roof behind the supports is allowed to fall LONGWALL MINING LAYOUT SHORTWALL AND CONVENTIONAL MINING . A shortwall uses a continuous mining machine in conjunction with hydraulic, self-advancing roof supports to cut coal panels Typical panels are 150 to 200 feet wide and over a half mile long . Conventional mining is performed by: Cutting a slot under the coal seam Drilling holes in the seam Loading holes with explosives Blasting the coal . These mining methods are rarely used in the US today UNDERGROUND MINE LAYOUT SURFACE MINING . Surface mining methods are generally more productive than underground mining methods . 90% of the coal mined west of the Mississippi River is produced by surface mines . 40% of the coal mined east of the Mississippi River is produced by surface mines . Productivity from western surface mines in 2005 was 21.30 tons per total employee-hour, compared to 3.27 tons per total employee-hour from eastern surface mines TYPES OF SURFACE MINING METHODS . Major surface mining methods include: Area Mining Contour Mining Mountaintop Removal Highwall Mining Auger Mining AREA MINING . Surface mining where the surface is flat or gently rolling . Draglines and/or shovels are used to remove the strata overlying the coal . Draglines typically can move up to 120 cubic yards per bucket load . Shovels typically can move up to 70 cubic yards per bucket load . The overlying strata may have to be drilled and blasted with explosives prior to being moved with draglines or shovels . The overburden material is replaced after the coal has been removed AREA MINING DRAGLINE MINE SHOVEL AND TRUCK COAL LOADER DRILL DOZER CONTOUR MINING . Usually associated with a coal seam that outcrops at a certain elevation above drainage in a mountainous mining region . Mining follows the seam outcrop around the hill or mountain . Overburden material is either hauled or pushed . Mined-out contour benches are reclaimed and re-seeded CONTOUR MINING MOUNTAINTOP MINING . Used to recover coal seams which are close to the top of hills or mountains . All the strata above the coal seam(s) is removed . Overburdened material is backstacked or placed in valley fills . Mined areas are reclaimed, which provides a suitable site for various development opportunities MOUNTAINTOP MINING HIGHWALL AND AUGER MINING . Highwall mining and auger mining are generally used to recover coal after contour mining has been completed . Highwall mining uses a continuous miner cutter head to advance into the coal seam from the highwall . Highwall mining can extend up to 1,000 feet into the coal seam . Auger mining uses a drilling tool with screw-like extensions to penetrate and extract the coal . Auger mining can extend up to 250 feet into the coal seam HIGHWALL MINER AUGER MINE COAL PREPARATION . Underground mined coal is typically transported by belt conveyors to a preparation plant located on the surface . Surface mined coal is typically hauled by trucks to the preparation plant . Purpose of coal preparation is to improve the quality of the run-of-mine coal to make it suitable for marketing . Type of coal preparation primarily depends on: The inherent quality of the coal Customer specifications COAL PREPARATION . Surface mined coal is typically hauled by trucks to the preparation plant . Improve coal quality and marketability by: Cleaning to remove inorganic impurities Sizing, crushing and/or screening . Primary coal preparation methods include: Jig Dense medium separators Floatation Spirals COAL PREPARATION PLANT COAL MINING REGULATIONS . Safety in coal mining is highly regulated, requiring great diligence and close cooperation by management, the workforce and the . Coal mining is one of the most regulated industries in the US government agencies . Companies must comply with literally hundreds of operating and . The Coal Mine Health and Safety Act of 1969 is the major safety environmental requirements and regulations directive for federal regulations governing safety in the industry . Considerable planning by mining engineers and operating . Regulations governing the mining industry are enforced by the Mine personnel, relative to all aspects of the operation, is required before Safety and Health Administration (MSHA), in compliance with Part permission from local, state and federal government agencies is 30 of Code of Federal Regulations for Mineral Resources granted to develop a coal mine . Compliance to the regulations is mandatory for each surface and . As long as ten years can elapse between starting to plan for a mine underground mining operation in the US and mining the first ton of coal .